1. Field of the Invention
The invention relates to a lens and a lens module, and more particularly, to a zoom lens and a zoom lens module.
2. Description of Related Art
Following advances in modern video technology, demands for high-pixel, high-quality lens of digital video camera (DVC) and digital camera (DC) are gradually increasing in recent years, and are developing towards miniaturization, large aperture and wide viewing angle. A core component of the imaging devices is a zoom lens, far and near images can be formed more clearly via an optical zoom of the zoom lens; therefore, an optical quality of the zoom lens is closely related to an imaging quality of the images. In a highly competitive market, various companies are all committed to improve the quality of the zoom lens and reduce a production costs thereof, so as to enhance competitive advantages of the imaging devices.
Nevertheless, a current design of a periscope-type zoom lens, due to a relative difficulty in processing, and subjected to a more strict tolerance, is more difficult to achieve all of a high-resolution feature, a large aperture advantage and a wide viewing angle. Moreover, a small aperture is prone to dilemmas of a shortage of luminous flux, more noises and underexposure when applied in a night use of the digital camera. For example, F-numbers of the apertures disclosed in U.S. Pat. No. 7,466,500 and U.S. Pat. No. 7,180,684 are both 3.5 or more, and thus are easily faced with a problem of inadequate luminous flux.
In addition, a zoom lens provided by U.S. Pat. No. 7,286,299 not only fails to meet the demands of large aperture but also has a small field of view (FOV) (2ω), thus leading to shortcomings of shooting range shrinkage and inadequate luminous flux, such that the user demands are not able to be fulfilled.
Besides, a zoom lens is disclosed in U.S. Pat. No. 7,375,901, wherein the zoom lens includes four lens groups. Furthermore, a zoom lens including four lens groups is also disclosed in US Patent Application Publication No. 20120026603.